2000 410 DA tach

[highball]

I have a 2000 410 DA with 7.4 Horizons ( yes gas !!) and the tack on port side is driving me crazy !!!!
When I bought the boat a few years ago the tack was working on and off when it felt like it. One day good the next would stay at 1500 RPM. the hour meter works fine but tack itself ?????
I found a new one and put in last summer. It seemed to work fine last year but this year same thing as the previous one.
I did the knob in back thing ( turn one side and the other put back on 8 position no go.
If I take the wires from the starboard side ( yes port is fully disconnected) it works with other wiring.
I suspect the signal wiring from motor might be broken or ????
Where would the wire be connected and what colour ???
Usually a tack is connected to coil but the wiring on guage and tack don't match
Any help would be greatly appreciated​

 

[mistercomputerman]

 

[highball]

Thanks Mr Computerman
I will check in two weeks when I'm back to boat and will try and find it on motor. Guess will need to follow grey wire. Do you have an idea where the tach sender is ????

 

[mistercomputerman]

I can't help you on that one. I traded out the 7.4s for 8.1s a couple of years ago.

If you do not see anything wrong with the wire, then probably need to find the plug and cap labeled #28 and check that the plug is secure in the cap.

You may run a temp wire from the sender to the tach to see if the problem is solved before you go chasing a ghost.

 

[highball]

That's why I wanted to know where on engin. if playing with plug don't work I wnat to run a tempory wire to see if issue is solved. If this works then I will run a wire to be there for many years !!!
Thanks again

 

[mistercomputerman]

 

[highball]

thanks very much mistercomputerman.
Will check this out